Pentax K-5 Hands-on preview

Pentax K-5 with vertical grip D-BG4 and
lens DA* 55/1.4

Photokina
2010, the world's largest and most influencial
photographic fair, has just closed its doors last Sunday.
Monday, the day before Photokina officilally opened
its doors in Cologne, members of the international press
had a chance for a sneak preview and Pentax managed to
show prototypes with firmware 0.30 of their new Pentax
K-5 camera in the afternoon. I later consolidated my impressions
at a further visit. However, any sample shots shown here
are from Monday where all over Photokina, journalists were
happily forcing their SD cards into whatever camera which
appeared to be new. Pentax then better controlled it during
the official show but, e.g., Nikon simply did not have
enough staff to prevent people from putting their SD card
into the new D7000. Me being no exception :)

So, I put the following disclaimer upfront: Any sample shot
from the K-5 found on the internet today is not endorsed
by Pentax and no conclusions must be drawn from it. It is
from a prototype camera with preliminary firmware flewn into
Cologne by Hoya the day of the announcement (2010 September,
20).

These are my preliminary impressions from my short test
drive:

1. The announcement

The Pentax announcement was a bit unlucky.
Corporate Pentax was late for the event and announcements
have been
full of little mistakes, contradictions and appeared to be
rushed out. This did not exactly help in creating any enthusiasm
for the K-5 among the press. Pentax missed the opportunity
to hold a press conference on Monday or Tuesday too. Maybe
with an invited speaker from Tokyo and showing some pride
in the product. What a pitty. So, the general reception of
the K-5 is that of
a K-7Super
or
a K-7mkII.

So, now it is important to have a closer look
at the new Pentax flagship model which is going to hit
the market
soon. Maybe, the camera is able to create the excitement
all by itself which is what happened with the popular K-x
camera.

2. Market positioning

The Pentax K-5 is a semi-professional or enthusiast-level
SLR camera and competes with its peers from Nikon and Canon,
like the Nikon D7000, Nikon D300s and Canon 7D. Esp. the
D7000 looks like an identical copy of the K-5, and if the
K-5 is just a refreshed K-7, then it would be clear who copied
who ;)

It is exciting that the K-5 is defending Pentax' market
position in the market spot pretty much created by the K-7
(robust and compact and suitable for professional use). A
spot which obviously attracted Canon and Nikon and now appears
to be the most interesting market spot above $1000. According
to a recent DPReview poll, D7000, Fuji X100 and K-5 are the
most exciting Photokina news and then K-5 may be just a
refreshed K-7.

3. Availability and price

The MSRP of the K-5 body is $1,399.- USD. Pentax is confused
enough to not acknowledge this fact with their international
corporation
and to publish list prices as high as $1,599.- USD. I understand
that Pentax was caught with their pants down when Nikon launched
their D7000 body at $1,199.- USD just days before Pentax
was going to announce their K-5 at a price, I am pretty sure
about, closer to that of the D300s or 7D. But hey, if Pentax
Germany can respond in a timely fashion, why not the corporation?

The German MSRP as announced at Photokina is 1,449.- € incl.
19% VAT and e.g., French online store digit-photo.fr already
lists the K-5 body at 1,249.- € TTC and the D7000 body at
1,169.- € TTC, only 80 € less.

Both, K-5 and D7000 are announced to ship in October 2010
and you read it here first: when they hit the market, they
will sell at equal price. And both cameras should sell
very well, according from the first feed back I see.

4. Specs and first touch

That's easy: it looks and feels like a K-7. For many, this
means they fall in love with the camera immediately. For
some, it means the body is a bit small and the grip then
may help
or not. I tried the D7000. I am partial, I admit (for a subjective
question like this). But the D7000 could not create the same
kind of emotion when
I tried
it. At high ISO, one sees the lower noise floor in zoomed
view, with the 18-55 kt lens, one feels the more aggressive
AF, but other than that, it feels "K-7". With one notable
exception: contrast AF. It almost feels like Pentax leapfrogged
Canon and Nikon.

I hate redundancy on the web. So, rather than repeating
what is easily found elsewhere, I refer to the sources for
the specs and walk-thru:

Therefore, here I will focus on exclusive content maybe
not found elsewhere. If you aren't familiar yet with the
K-7 or Pentax cameras, you may want to start reading
with any of the links above.

5. Image quality

Currently, everything I've seen let me hope that the
image quality turns out to be impressive when studied
in more detail. As far as I know, Pentax uses the Sony
Exmor HD 16.2 MP APSC CMOS sensor with integrated column-parallel
A/D-converters. Which may be the same as in the Nikon
D7000. Pentax confirms using a sensor with embedded A/D-converter
and that's all it needs ;)

5.1 High ISO noise

Because the interest is huge and because high ISO JPEG
samples are already floating the web, I decided to publish
one ISO 6400 RAW sample. I took it Monday when all journalists
played their card party but I respect Pentax interest
to keep image files under closure. The RAW sample is
less affected by changes to the firmware which is why
it may be in the interest of Pentax to have at least
one RAW if JPEGs are already in the wild. The high ISO
JPG
samples
benchmark
the in-camera v0.30 JPG engine first of all and should
not be compared to D7000 JPGs.
My RAW may provide an alternative.

The RAW published here has been already developed using
various raw converters and NR settings, esp. in a very
vivid thread at pentaxforums.com and by Gordon
Goodman at dpreview.com. The general conclusion I
draw from the discussion is:

K-5 allows it to use AUTO-ISO ranges of up to ISO
6400 without hesitation (if it used to be 1600 like
on my K-7). Some
noise is visible, but is well treated by NR.

At ISO 6400, the advantage wrt K-7 may be about 2 stops
(almost). As I refuse to run quantitative lab tests yet,
this is
impossible to say exactly. This has to await until Pentax
thinks it makes sense to run a lab test.

Looking at Pentax K-x and Nikon D7000 and D5000, the
performance looks similiar. The K-x has less pixels to
be taken into
account too. For me, it is currently difficult and too
early to rank the three cameras.

At lower ISO settings like ISO 1600, the advantage
wrt K-7 is less. As to be expected if the progress comes
from lower read-out noise rather than a higher quantum
efficiency. ISO 400 shooters may be able to increase
to ISO 800 only. Physics can't be beaten.

So, a first assessment is possible: The high ISO noise
of the K-5 is within the best of its class.

Gordon B. Good went a step further and analyzed
the raw histogram in the DNG (cf. link above). His
conclusion (which can only be preliminary) is that
pixel read-out noise (dark noise) is even less than
with the Pentax K-x which excels in this regard.
He found too that ISO 6400 is created from an ISO
1600 capture then boosting EV by +2 in camera.

5.2 Dynamic range, colors, pattern noise, AA filter,
resolution

To the right is an unprocessed image out of the
Pentax K-5 camera at ISO 100. So yes, the camera
works at ISO 100 :)

If Gordon's preliminary analysis holds true (he
looked at an ISO 1600 PEF too), then a pixel's full
well capacity is on par with a K-x and the minimum
recordable luminosity of a K-5 pixel
should beat the value of 0.021% for
the K-x (dynamic range as defined by an SNR of 0dB).
E.g., a value of 0.017%
(corresponding to Gordon's 2/3 black noise remark)
at K-5's resolution would correspond
to a dynamic range
of 13.0 EV in DxO's terms. That would be
a stunning value for an APS-C camera. 0.017% would use
12.5 bits (out of 14) too which makes the 14 bit
format
not
a complete loss,
compared to 12 bits which is an industry's first.
If this analysis can be
verified to hold true after production cameras ship.

Update: more recent remarks (made after analyzing
the ISO 80 RAW black noise) claim dynamic range to
be even better than 13EV. I'll soon edit this sentence
to reflect a common preliminary assessment by Gordon
and myself.

I did not evaluate color rendition, pattern noise,
AA filter, and resolution.

5.3 Shutter blur

I'll take a detailed look at that as soon as I can.
So, while I refuse to comment on the issue for the
time being, I can still quote others who tried to
find out,
can't I? Ok, several other tried to see the shutter
blur on the K-5 (in magnified playback) and told me
to have a good feeling
because they couldn't find it. Would they have seen
it with a K-7? I don't know. But it is a positive
sign and
therefore, let's take it as such.

6. Autofocus performance

6.1 Phase AF

The K-5 uses a similiar AF module (SAFOX IX+) to the
K-7 (SAFOX VIII+), but with larger AF lenses and/or more
sensitive AF sensors. It has 11 AF sensors, 9 which of
are cross type. All sensors are f/5.6, so it has no f/2.8
dual type center sensor (as far as Pentax Germany knows).

The AF performance in good office space lighting with
the 18-55 mm screw drive kit lens is outstanding: It
makes a
noise which is so short that it sounds a bit like the
AF hit the limiter. The algorithm has
the SAFOX gene: if the focus has to travel (isn't close
already), then the lens may be refocussed a second (or
in rare cases) even a third time. But it is so fast one
is not necessarily aware of it. I think it is a good
thing that the Pentax AF still verifies focus "on
arrival"
and doesn't trust it blindly which may not be as accurate.
But it can increase shutter delay. I didn't check if
the new shutter priority modes in the K-5 AF settings
bring a change in this respect.

I heard reports (caution: hearsay!) that the new DA
35/2.4 lens has a very remarkable high focus speed as
well.

Wieland (aka blende8 from pentaxforums.com) and myself
brought two DA* 16-50/2.8 SDM lenses and compared head
to head,
K-5 vs. K-7. It was difficult to tell if
the K-5 was faster. The SDM speed is the same as for
the K-7, limited by the lens motor. Wieland
(who has
it on video) and myself verified this. Lens travel was
the dominating part in focus time. But for short lens
travel (prefocus) I
got the impression that the remaining focus time for
the K-5 is significantly smaller. This must be benchmarked
really. Moreover, Pentax Japan specifies autofocus operation
to be possible at -1 EV. That may be false information,
requiring the AF assist beam or be an impressive figure.

I didn't test continous autofocus. According
to pentaxeros.com,
the throughput in usable photos in AF.C may have
doubled, relative to a K-7. Overall, my preliminary
impression is that the progress made in autofocus
performance from the K20D to the K-7,
and from the K-7 to the K-5, may be comparable. This
may or may not suffice to compete with a D7000 or 7D
in this department.

I made a short test if the K-5 tries to track AF points,
i.e., if the K-5 tries to predict the hop of a subject
from its active AF point to the next. My preliminary
impression is that
the
K-5 doesn't
do that and it would be difficult with 11 AF points anyway.

I tried the AF in the new Nikon D7000 and the new Sony
SLT55 as well. I wasn't overwhelmed by the D7000 (the
lens didn't have a fast focus though) and the SLT55
was cool. Sony had a half pipe with skate boarders and
bikers
and plenty of action. The SLT55 AF.C performed considerably
faster than my K-7 (I loved to have a K-5 there but
Pentax staff would have tortured me afterwards ;) ).
But the K-7
didn't fail entirely and the SLT55 didn't perform flawlessly.
In the end, the number of usable photos per half pipe
turn may have been twice in Sony's advantage. Twice
"only", maybe not out of reach for a K-5.

6.2 Contrast AF

The contrast AF seems to be a complete rewrite. When
you half press the shutter (or whatever activates AF)
the live view image zooms into the appropriate focus
rectangle and confirms with green border and beep, then
zooms out. The entire process takes about 1 s. Compare
that to phase detect AF which typically took about 0.4
s and then contrast AF is only slower by a factor 2-3.

It's even possible to switch contrast AF into AF.C.
But the performance is poor: it only refocusses every
4 seconds
or so when the change in contrast is obvious. But this
is for a prototype firmware. Pentax may still work on
this.

Another positive surprise is that contrast AF doesn't
pump a lot (anymore).

Overall, my preliminary impression is that the K-5 (and
K-r too) are the first Pentax SLR cameras where contrast
AF is really usable. At least for subjects which don't
move fast.

The new contrast AF should now be fast enough to allow
AF during movie recording. But firmware 0.3 shows no
signs of such a feature: pressing AF in video has no
effect and there is no menu option for it. Pentax Germany
says that they received no information regarding AF during
video and it's not on the Japanese spec sheet either.

7. Live view

Except AF operation, LV looks the same as with the K-7.
In manual focus mode, there still are additional 8x
and 10x magnification steps. However, unlike with the
K-7,
the image quality doesn't seem to increase in the additional
magnification steps: diagonal edges had a very visible
staircase effect which was symmetric. The K-7 reduced
the effect in one direction with the additional
magnification steps at the expense of a slower frame
rate. Overall, it's probably about the same to manual
focus in live view. The resolution still seems to be
limited to that of HD video. There is no auto-zoom in
manual
focus, e.g. by half pressing the
shutter.

8. Video

One frame from a K-5 720p HD
video (click for 100% size)

The K-5 sports 1080p HD video at 25fps (up to 25
min or 4GB). And smaller sizes at 25fps and 30fps.
So, the
sensor's read-out rate or processor performance are
not sufficient for 1080p at 30fps and only Pentax
knows why
then they didn't incorporate a 24fps mode.

Video quality
looks good but that's only a preliminary statement.
I can see traces of pixel artefacts in the frame
as are typical for all current video SLR cameras
because the sensors must be subsampled. Note that
the quality in production cameras can even be substantially
better.

There are no manual controls (for shutter and ISO, that
is) in movie recording, just manual aperture, exposure
compensation and lock. The audio recording in the K-7
was fixed gain (manual only so to speak) and it may be
the same for the K-5. I did not check it.

Pentax Germany had requested manual video controls in
Japan. Obviously, it did not help much.

The K-5 has a programmable RAW button (Fx). The press
material mentions that the video mode can be activated
this way. Which is a great thing because turning the
mode dial every time is awkward. Moreover, one could
theoretically
switch the mode dial to "M"and activate video,
hoping that ISO and shutter controls are enabled (hope
dies
last). But I couldn't test because the video function
for the Fx button was still missing in the firmware.
I hope the press material is right about the possibility
to map Fx to video. Because turning the locked mode
dial every time is awkward.

9. HDR

In-camera HDR (high dynamic range) photography was
pioneered by Pentax with the K-7. But they ommitted
the feature to align images in-camera too which made
the feature obsolete without a tripod. I demonstrated
in
a LumoLabs article right here that the K-7 hardware
should be capable enough to do the alignment in-body
as
well. Pentax ignored me but they did not ignore Sony
who then implemented the full feature in their NEX
mirrorless cameras. So, the K-5 does now support
in-camera image alignment too and additionally provides
additional rendering parameters. Below is my free-hand
HDR example using the various settings:

(click on the thumbnails for full size samples,
appropriate to inspect alignment quality -- hover
over a thumbnail to see the HDR setting)

Most of the time, the alignment works well and the
HDR feature is a powerful extension of a photographers
arsenal. The processing time is acceptable. However,
the alignment isn't flawless (e.g., look at the "strong
2" sample in full size). Maybe, Pentax wants to license
the LumoLabs algorithm? ;) Another disappointment
is that the processor still doesn't write a linear
DNG raw file without any tone mapping applied. And
eventually, the alignment could have been available
in multiexposure mode too but isn't. Sony calls the
latter feature "steady night shot".

Nevertheless, Pentax and Sony are pioneering new
creative possiblities with their cameras and this
gives them an innovative edge wrt Nikon and Canon.

10. Many more things ...

The sections below are answers to questions I received
via comments to my blog or forum posts.

10.1 RAW file bit depth and buffer size

The K-5 has an increased bit depth (from its A/D converter
to RAW storage/processing) and increased number of
pixels. An uncompressed RAW frame is 28.3 MB
or 1.31x as much data
as it was on a K-7. Which would reduce the buffer capacity
to 10 raw frames (down from 14-15 on the K-7) somewhat
in line with the Pentax specification of 8 raw frames.
At
7
fps, this means that the
buffer fills
in 1.1 s (down from 2.7 s on the K-7). I confirmed
by trying it out that the hi speed burst lasts for 8
raw frames. This means that the overall buffer size and
write speed to SD card have remained the same.

The fps or bit depth cannot be configured and Pentax
has no plans to release a mid speed burst mode where
the
buffer
fills
more slowly. Pentax thinks that action shot
bursts are done in JPG and RAW bursts are mainly for
bracketing and similiar applications.

It wasn't specified but the K-7 had an easter egg: With
a high speed SD card, low quality JPG setting and all
settings manual, the K-7 could burst at 5.2 fps until
card full! The K-5 cannot do it anymore. Even at lowest
quality settings and with a Sandisk Extreme III card,
the burst breaks slow after about 29 JPGs or 4 seconds.

10.2 Prime II processor

The press material creates the impression that the Prime
II image processor is changed. This isn't true. The DRAM
memory (2GB AFAIK), the clock speed and processor itself
(Prime II) are the same as with the K-7. Maybe, some
of the algorithms are different (more pixels, 14 rather
than 12 Bits) but that does not qualify the image processor
to be considered "upgraded".

I compared the processing speed for lens corrections
(CA+distortion). The image on the display of the K-7
appears just a second or so before that on the K-5. Which
is exactly the expected difference with an extra of 11%
more pixels to process on the K-5. For an image processor
of equal speed that is.

10.3 Shake reduction

I could find no differences in the shake reduction feature.
The specification didn't change either. However, there
is a small change I noticed nevertheless: When you half
press the shutter, the SR needs about a second to get
ready.
About
the same for K-7 and K-5. But if you unpress the shutter,
the SR stays ready until the VF INFO row is switched
off a couple of seconds later. With the K-7, it didn't
and another half press always had the delay for SR to
get ready again. This may be a huge difference in certain
situations. If it wasn't simply a display bug, then or
now.

10.4 Top LCD light

The top LCD illumination is either on or off (depending
on a menu setting) which is like the K-7 and unlike K20D.
Most people like the K20D method better.

10.5 Bulb mode and DFS

DFS (Dark frame subtraction aka Long exposure noise
reduction) can now be switched off even for bulb mode
(exposures longer than 30s). I made a test with a 66s
exposure at
ISO 1600 and the image displayed immediately and the
camera was ready again -- without a delay (firmware 0.30).
ISO 1600 is the highest ISO setting for bulb mode. This
is no limitation for raw shooting though because higher
ISO are made in camera from ISO 1600 by exposure boost
post processing; something easily done in the raw converter
as well.

10.6 Tethering

The K-5 ships without a true tethering solution. An
EyiFi card, remote trigger and HDMI connection are the
only means available now. Pentax Japan confirmed to Pentax
Germany
that their
request for a tethering solution has been acknowledged
without saying if Pentax is going to release a tethering
solution or not.

10.7 Flash sync time

The K-5 has a flash sync time of 1/180s. The rumor about
a sync time of 1/250s, maybe in conjunction with faster
Pentax flashes to be released soon, has been disclaimed
by Pentax Germany.

10.8 SXHC support

The K-5 will receive SXHC support via a firmware update.
This has been made public by the Pentax Imaging USA web
site.

10.9 Intervall shooting

The K-5 allows to select the number of intervall shots
to be between 1 and 999 (up from 99 on the K-7). The
selection is by digit.

10.10 User modes

The K-5 now has 5 user modes. However, there is
only one user mode position on the mode dial and
you'll have to select which one of five modes to
use.

10.11 Level meter

The K-5 has a level meter for two axes (roll and pitch).
The K-7 has roll only. However, the K-5 only shows the
roll level in the viewfinder and the top LCD. The rear
LCD shows both.

10.12 Exposure bracketing with MLU

The K-5's Fx button can be configured to enable exposure
bracketing to later produce HDR images -- with a single
button press. However, on the K-5 and K-7, mirror lock-up
(MLU) and exposure bracketing are mutually exclusive
drive modes. Theoretically, the Fx button solution could
solve this. However, an Fx button press selects the exposure
bracketing drive mode and thereby deselects the MLU drive
mode if it was selected before. No luck.

Nevertheless, exposure bracketing with mirror lockup
is available on both the K-5 and K-7: use exposure bracketing
from within live view (LV). Because of the improved LV
focus performance this is a serious option with the K-5
actually. The Nikon D7000 calls it "quiet mode" and has
it as a new feature.

10.13 Shutter noise

I compared a K-5 and K-7 side by side. They have
identical shutter noise (at least without MLU and
with no burst -- as I didn't check for those). Which
means that K-5 continues to be state-of-the-art in
this field.

Conclusion

This concludes my hands-on preview report of the Pentax
K-5 semi-professional APS-C SLR camera. It combines what
may currently be the best APS-C sensor with a camera
which has almost professional grade attributes but in
a package which pleases the outdoor and street as well
as the enthusiast photographer. It shares the genes of
the applauded K-7 and improves on the three
points which could have been considered its only weakness:
ISO performance, autofocus speed, uncommon sources for
blur (maybe).

The K-5 has only two rivals which however, can't beat
it (except maybe for very fast action and long lenses):
the very similiar Nikon D7000 and the bulkier and more
expensive
Canon
7D. If you now consider that only Pentax managed to pack
a good sensor-shift stabilizer into the body which is
the
most elegant, sturdy, lightest and smallest of the three
and is done by the smallest company of the three, then
the
K-5 is an engineering gem and a photographer's pleasure.
No wonder it is the only SLR to receive this year's Photokina
Star 2010.